Magnetically driven crustquakes in neutron stars
Magnetically driven crustquakes in neutron stars
Crustquake events may be connected with both rapid spin-up `glitches' within the regular slowdown of neutron stars, and high-energy magnetar flares. We argue that magnetic-field decay builds up stresses in a neutron star's crust, as the elastic shear force resists the Lorentz force's desire to rearrange the global magnetic-field equilibrium. We derive a criterion for crust-breaking induced by a changing magnetic-field configuration, and use this to investigate strain patterns in a neutron star's crust for a variety of different magnetic-field models. Universally, we find that the crust is most liable to break if the magnetic field has a strong toroidal component, in which case the epicentre of the crustquake is around the equator. We calculate the energy released in a crustquake as a function of the fracture depth, finding that it is independent of field strength. Crust-breaking is, however, associated with a characteristic local field strength of 2.4 × 1014 G for a breaking strain of 0.001, or 2.4 × 1015 G at a breaking strain of 0.1. We find that even the most luminous magnetar giant flare could have been powered by crustal energy release alone.
2047-2058
Lander, S.K.
f9fe4b41-e092-4bcb-869d-080996442dd1
Andersson, N.
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
Antonopoulou, D.
3d6a3e07-b935-4270-8ca0-97336266fece
Watts, A.L.
17b5168f-b189-45d4-a639-c5b0fe55d9ff
27 March 2015
Lander, S.K.
f9fe4b41-e092-4bcb-869d-080996442dd1
Andersson, N.
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
Antonopoulou, D.
3d6a3e07-b935-4270-8ca0-97336266fece
Watts, A.L.
17b5168f-b189-45d4-a639-c5b0fe55d9ff
Lander, S.K., Andersson, N., Antonopoulou, D. and Watts, A.L.
(2015)
Magnetically driven crustquakes in neutron stars.
Monthly Notices of the Royal Astronomical Society, 449 (2), .
(doi:10.1093/mnras/stv432).
Abstract
Crustquake events may be connected with both rapid spin-up `glitches' within the regular slowdown of neutron stars, and high-energy magnetar flares. We argue that magnetic-field decay builds up stresses in a neutron star's crust, as the elastic shear force resists the Lorentz force's desire to rearrange the global magnetic-field equilibrium. We derive a criterion for crust-breaking induced by a changing magnetic-field configuration, and use this to investigate strain patterns in a neutron star's crust for a variety of different magnetic-field models. Universally, we find that the crust is most liable to break if the magnetic field has a strong toroidal component, in which case the epicentre of the crustquake is around the equator. We calculate the energy released in a crustquake as a function of the fracture depth, finding that it is independent of field strength. Crust-breaking is, however, associated with a characteristic local field strength of 2.4 × 1014 G for a breaking strain of 0.001, or 2.4 × 1015 G at a breaking strain of 0.1. We find that even the most luminous magnetar giant flare could have been powered by crustal energy release alone.
More information
Accepted/In Press date: 23 February 2015
Published date: 27 March 2015
Organisations:
Applied Mathematics
Identifiers
Local EPrints ID: 410566
URI: http://eprints.soton.ac.uk/id/eprint/410566
ISSN: 1365-2966
PURE UUID: 8782217a-0dd9-4f67-86fb-5eb72542c486
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Date deposited: 09 Jun 2017 09:08
Last modified: 16 Mar 2024 03:02
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Contributors
Author:
S.K. Lander
Author:
D. Antonopoulou
Author:
A.L. Watts
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